Thrombi are often found in aneurysms and are considered to play an important
role in rupture. It is crucial to scrutinise any correlation between the probability
of rupture and the extent to which thrombi are generated in the aneurysm.
Numerical techniques such as computational fluid dynamics (CFD) are
promising tools in the biomedical field. However, there are, at present, no
models that allow us to evaluate thrombus generation. The authors aim at the
proposal of such a model. In the present study, the process of platelet
aggregation is considered. In blood flow near the entry to an aneurysm, red blood
cells are haemolysed due to high shear stress or high pressure. The ensuing
release of adenosine diphosphate (ADP) induces the aggregation. Making
reference to actual aggregation curves of human plasma for various ADP
concentrations, the authors have modelled the rate at which the density of
aggregated platelets continues to increase in the aggregation process. A
combination of CFD and the present model enables us to obtain the distribution
of platelets clotting in an aneurysm.
Keywords: computational fluid dynamics, platelet aggregation, aneurysm.
1 Introduction
Rupture of a cerebral artery aneurysm causes a life-threatening subarachnoid
haemorrhage. Although not all aneurysms rupture, it is difficult to predict which
aneurysms are likely to do so. Ujiie et al. [1] reported a significant correlation
between the probability of rupture and aspect ratio of the aneurismal dome depth
to the neck width: almost 80% of ruptured aneurysms among those investigated
by them had aspect ratio more than 1.6. According to a theory proposed by Ujiie
et al. [2], thrombi are likely to form in an aneurysm of high aspect ratio due to